1. Field of the Invention
This invention relates to a ground system designed to ventilate a variety of aircraft or structures especially executive and private airplanes.
2. Background of the Prior Art
When aircraft are parked on hot, sunny days, the interior temperature increases rapidly. Little ventilation is available. Many airplanes have only one door and no cooling air-conditioning. Air-conditioning must be powered, and it is uneconomical and possibly unsafe to use the main engine(s) to run an air-conditioner in a parked airplane.
The heating of the aircraft is a minor inconvenience when it is vacant, but a hot and/or humid airplane is most uncomfortable to embarking passengers. Because of the heat stored in the fuselage and contents of the airplane, the interior of the aircraft may not reach a comfortable temperature until well into the flight. Cooling does take place at higher altitudes where the air temperature is lower, but it may take many minutes to reach that altitude. The problem is compounded at major airports because there may be traffic delays in taking off. The problem is especially acute in executive jets and turboprop airplanes that may have pressurized cabins for flight at high altitudes. In those airplanes, the cabin is sealed before takeoff and the aircraft ventilation system cannot handle the preload of the heat in the plane. Occasionally also, an aircraft parked outside on a very cold day may be very cold inside and it may take many minutes into a flight before the passenger cabin is comfortably warm.
Various shelters may be used as warehouses, construction offices or the like. It may be uneconomical to provide these structures with permanent heating or cooling, but it may be desirable to heat or cool the structures on occasion.
Commercial airplanes have ground ventilation systems to ventilate parked airplanes. One of the earlier ones used a stand-alone air-conditioning unit mounted on a chassis for movement between aircraft parked at various gates at an airport. A flexible hose extended between the air-conditioning units and a fitting on the airplane for ventilating and cooling the interior of the airplane. Some commercial airplanes now have an auxiliary power unit APU which can be used for generating electrical power to run the ventilating systems and air-conditioning while the airplane is on the ground. The airplane may also be connected to an electrical source at the gate.
These options are not always available to executive and general aviation. They are not parked at a conventional gate, and few have an APU because of weight and cost considerations or have fittings for connection to the stand-alone air-conditioning units.